Weak Antilocalization and Spin Precession in Quantum Wells

TL;DR

This paper investigates how spin splitting affects weak localization in GaInAs quantum wells through magnetoconductivity measurements, developing a comprehensive theory that accounts for various spin splitting contributions and matching experimental data.

Contribution

The paper introduces a theory that incorporates both linear and cubic spin splitting terms in quantum wells, improving understanding of their influence on weak localization effects.

Findings

Different spin splitting terms significantly influence magnetoconductivity.

All three contributions are comparable within the studied electron density range.

The results help identify dominant spin relaxation mechanisms and refine spin splitting parameters.

Abstract

The results of magnetoconductivity measurements in GaInAs quantum wells are presented. The observed magnetoconductivity appears due to the quantum interference, which lead to the weak localization effect. It is established that the details of the weak localization are controlled by the spin splitting of electron spectra. A theory is developed which takes into account both linear and cubic in electron wave vector terms in spin splitting, which arise due to the lack of inversion center in the crystal, as well as the linear terms which appear when the well itself is asymmetric. It is established that, unlike spin relaxation rate, contributions of different terms into magnetoconductivity are not additive. It is demonstrated that in the interval of electron densities under investigation (0.98-1.85)*10^(12) 1/cm^2 all three contribution are comparable and have to be taken into account to achieve a good agreement between the theory and experiment. The results obtained from comparison of the experiment and the theory have allowed us to determine what mechanisms dominate the spin relaxation in quantum wells and to improve the accuracy of determination of spin splitting parameters in A3B5 crystals and 2D structures.